Solenoid relay with pneumatic stroke retardation



Jan. 1, 1963 w. PRIESEMUTH 3,

SOLENOID RELAY WITH PNEUMATIC STROKE RETARDATION Filed Sept. 9, 1957 2Sheets-Sheet J.

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Jan. 1, 1-963 SOLENOID RELAY WITH PNEUMATIC STROKE RETARDATION FiledSept. 9, 1957 2 Sheets-Sheet 2 //v vglvrog: W01 FGAM/tPR/ESEMUIH 6y a Mired Sttes Pa 3,071,664 Patented Jan. 1, 1963 3,071,664 SOLENOID RELAYWITH PNEUMATIC STPQQKE RETARDATION Wolfgang Herbert Priesemutlr,Danzigerstr. 35, ltzehoe, Holstein, Germany Filed Sept. 9, H57, Ser. No.632,846 Claims priority, application Germany Sept. 10, 1956 5 Claims.(Cl. 200-97) The invention relates to a solenoid relay with pneumaticstroke retardation. In particular, it relates to the embodiment of suchrelays as blinker relays and their use in blinker circuits.

Time-delay relays are known per so. It is likewise known that thereciprocating motion of the plunger may be retarded in both directionsby means of a pneumatic element.

However, known relays are of comparatively complicated construction, andmoreover consume a comparatively large amount of current.

The object of the invention is to devise such a relay that will admit ofa simple structure and consequently be of highly economical manufacture,such simple structure at the same time affording trouble-free operationin long continuous service.

For this purpose, according to the invention, a solenoid relay is soarranged that the plunger, electromagnetically attractable againstspring action, operates against a yielding air cushion upon its return.

According to a preferred embodiment, the body of the energizing coil isfashioned as an air cylinder for a pistonlike plunger, and the cylinderis further provided with a valve for unimpeded sudden air escape and apreferably controllable aperture for throttled flow. The plunger is thendrawn in solely under spring load, the free escape of air permitting nopneumatic restraint, so that this step requires no additional current.

Retraction follows under the action of the spring against the aircushion, now closed, the adjustable throttledoutlet being used to obtainthe desired return delay.

A relay of this type will serve a great variety of applications, and isextremely simple and reliable compared to known types of relays.

A further preferred embodiment consists in building such a relay in theform of a self-interrupter. For this purpose, according to theinvention, the plunger is provided with a contact slide actuable withplay within the stroke, and the coil'body is provided with a contactsystem for the energizing circuit to cooperate with the contact slide,in such manner that the contact slide is held back within its play bythe contact system during the initial stroke, while in the rest of thestroke the contact slide engages the contact system, opening theenergizing circuit, and is thenceforth held by it during the return ofthe plunger, using up the play. During the rest of the return stroke ofthe plunger, the contact slide is withdrawn from the contact systemagain, thus in turn closing the energizing circuit and recommencing thecycle of operations.

Such a solenoid relay with self-interrupter is extraordinarily simple tomanufacture and nevertheless very reliable in operation. It cantherefore be used to advantage in blinker circuits as well as for manyother similar purposes.

The invention further relates to a modification of the relay for use inblinker circuits in conjunction with incandescent lamps, and also to acombination with the latter.

For this purpose, a solenoid relay of the kind described is soconstructed that the free end of a leaf spring on the coil bodyoscillates laterally in the direction of motion of the piston betweentwo terminal points thereof and is held in one of its two positions by asnap spring.

In addition, the oscillating leaf spring is provided with pairs ofcontacts for the energizing coil and for a lightbulb circuit, contactingin the snap position at the beginning of the sucking stroke.

According to one embodiment, these pairs of contacts are so adjusted toeach other that contact for the light-bulb circuit occurs during thereturn stroke in advance of contact closure of the excitation circuit.

By this arrangement, it is possible to build satisfactory and dependableblinker circuits by means of incandescent lamps. Both the relay and thelamp carry current for only an extremely short time, so that there isvery low consumption. Owing to the brief closure of current, it is alsopossible to use lamps with low service voltage, so as to produce astronger flash effect.

A very important advantage, however, consists in that this relay systemcan easily be installed in the base of an incandescent lamp. Byappropriate circuiting, this produces an incandescent lamp with relay asa self-contained unit, the ordinary contacts of the lamp serving also ascurrent leads. Such a blinker light bulb may then simply be screwed intoa socket in a lighting circuit, and will produce a blinking light whenswitched on.

In this way, blinker circuits can be provided with great ease, simply inthe form of an ordinary lighting circuit.

Blinker lights of this kind are used for signaling purpose, particularlyin traffic signals, for the marking of con struction sites and the like.

By the use of blinker relays of the present type, it becomes a singlematter to install such warning blinker lights. A special factor is thesource of current, whether in the form of dry cells or in the form ofstorage batteries, since in the first place a long-term servicedependability and in the second place a certain minimum length ofservice are necessary. Also, it is essential for such warning blinkerlights to have an independent source of current, as in this casebatteries, so that they can be used anywhere and at any time.

Warning blinker lights using dry batteries can be installed quitesuccessfully with such a self-interrupter relay, a size and type simpleto operate and economical to manufacture.

But such warning blinker lights using dry batteries as source of currenthave another important disadvantage, namely that their preparedness forservice is uncertain for a time. When new batteries are used, it isknown that the requisite service life, in fact a multiple thereof, isavailable. When the batteries are exhausted, the interrupter relay failsto function, so that this circumstance can also be identified. In theuse of warning blinker lights, however, it is necessary to be able totell whether serviceability is assured for a certain length of time tocome, which is to say that these should be a means of testing the lightsat certain intervals. Permanent readiness for service cannot even besecured by regular change of batteries, because consumption in serviceis not directly apparent. Besides, even when not used, dry batterieshave extreme storage sensitivity.

Now the present invention further relates to an improvement in warningblinker lights for overcoming these disadvantages, by providing simplemeans of checking future service life at any time. For this purpose, thecircuit of interrupter relay, blinker light and battery, is providedwith an auxiliary connectable resistance. This resistance may forexample be in parallel with the switch, and briefly connected by meansof a pushbutton. The resistance may, alternatively, be directly inseries with the circuit and bypassed by a pushbutton switch which can bebriefly opened, so as to be short-circuited in normal position of thepushbutton. In either case, therefore, the resistance is introduced intothe circuit by means of a pushbutton. The value of the resistance shouldfurther be such, in relation to the operating resistances of the lightand relay 3 coil, as well as to the service voltage of the battery as itdischarges, that when a certain degree of discharge is reached, or inother words when the service voltage of the battery drops to apredetermined value, the relay coil fails to respond to the current inthe circuit with the resistance connected. Preferably, the condition ofdischarge of the battery, and the corresponding undervoltage, should bechosen such as to ensure that the battery is good for a certain minimumadditional period of time. For example, it may be required that suchwarning blinker lights be ready for fifteen hours continuous service.Then it is readily possible to determine a resistance value such thatthis requirement is met in terms of the other factors.

When the test key connecting the auxiliary resistance is actuated, theblinker light will be found to operate normally within a certaindischarge interval. When discharge has progressed to a certain point,the relay will fail to respond, and the blinker light will be litcontinuously while the test key is being actuated. This will mean thatthe blinker light with batteries as is will not last for the requiredperiod of service and that the batteries must be charged.

But if the light blinks while the test key is being actuated, theblinker light will operate for the required minimum period or" time.These simple means therefore permit a permanent check-up on the blinkerlight, as required under existing regulations for use in traflic.

The device according to the invention will now be more fully describedwith reference to the accompanying drawings, but it should be understoodthat these are given by Way of illustration and not of limitation andthat many changes in the details may be made without departing from thespirit of the invention.

in the drawings:

FIG. 1 schematically shows a vertical section of a solenoid relay withplunger piston;

FIG. 2 shows a cross section of the same, through the plane of contact.

FIG. 3 shows a vertical section of a solenoid relay withself-interrupter.

FIG. 4 shows a cross-section of the relay of FIG. 3, through the planeof contact;

FIGS. 5 to 7 are views similar to FIGS. 3 and 4 showing anotherembodiment of a solenoid relay;

FIG. 8 shows a solenoid relay combined with an incandescent lamp.

FIG. 9 shows a circuit digram of a warning blinker light withincandescent lamp and relay in series; and

FIG. shows a similar circuit digram with the relay and lamp arrangementconnected in parallel.

In FIG. 1, a core or coil body 1 with a cylindrical bore forming anelongated chamber of substantially uniform cross-section, carries anenergizing winding 2. At the base of the cylinder there is an aperture 3covered by a valve disc 4. The valve disc 4 may consist of a yieldingmaterial such as rubber, or of a thin sheet of metal held against thecoil body by its own elasticity or by means of a separate spring, andcovering the aperture 3 in the manner of a check valve. The aperture isso arranged as to permit free escape of air, while entry of air isprevented. In the cylindrical bore, the piston-like plunger 5 moves inaxial direction against a spring 6 and forms an armature. A contact head7 is fixedly mounted on the plunger 5. Active contacts 8 and 9 mountedon the coil body are engaged by the contact head 7 in indrawn position.

As soon as the energizing circuit is closed, the plunger 5 is attractedunder the load of the biasing spring 6, the air escaping from thecylinder unimpeded by the unidirectional valve 4 through the valveaperture 3. This process takes place substantially without retardationand without load due to air compression. When the energizing circuit isopened and the plunger 5 returns under the action of the spring, thevalve aperture will be closed, so that accordingly a delay occurs. Forthrottle entry of air, a smaller auxiliary aperture 50, preferably withan adjusting screw 51, may be provided. Alternatively, throttledadmission of air for the return may be achieved by suitable conformationof the piston plunger and the cylinder with a certain amount ofclearance.

The solenoid relay with self-interrupter according to FIG. 3 isessentially similar to that of FIG. 1, with the difference that rod 10is secured to the piston-like plunger 5 and extends outwardly of thesolenoid and the contact head 7 displaceable thereon with a certainamount of play. The contact head 7 slides on the piston rod and isretained with play by an abutment or nut 16. The contact system hereconsists of two contact springs 11 and 12 arranged diametrally oppositeeach other on the sides of the coil body and pressing against each otherby means of lateral arms 13 and 14, thus making the contact connectionfor the energizing circuit. When the plunger 5 is attracted, the contacthead 7 will rest on the ends of springs 11 and 12 and be held by themwithin its displacement travel, namely for most of the instroke,whereafter during the rest of the stroke the contact head 7 is forced inbetween the pair of springs 11 and 12, separating the contact arms 13and 14. The actuating circuit is opened and the piston begins to return.During this return, the contact head 7 is at first retained by springs11 and 12 within its play, until in terminal position it will bereleased during the remaining return stroke, so that the arms 13 and 14make contact again. The actuating circuit is again closed, and the cyclerepeats itself.

Between the contact head 7 and the nut 16 limiting its play, it may bedesirable to provide another spring 15 to avoid flutter of the slidingcontact head. The play may be variously adjusted by setting the nut 16.This results in a corresponding adjustment of delay, as does theaforesaid regulation of air admission. Both means of adjust ment may beprovided, or only one of them.

The embodiment according to FTGS. 5 to 7 is essentially similar to thatof FIGS. 3 and 4. The coil body has been enclosed in an iron casing 17.The contact head 18 is again held displaceable with play on the pistonrod 10 by means of the nut 16. The contact head 18 bears two lateralarms 19, preferably of non-conductive material, cooperating with twopairs of lengthwise springs 20 and 21 mounted on the coil body. Thepairs of lengthwise springs 20 and 21 bear contacts 22 which touch innormal position, closing the actuating circuit. In addition, stops 23,preferably rounded or beveled, are provided, to stop arms 19 duringdisplacement within the play. The same cycle of operations takes placeas above.

In FIG. 8, a solenoid relay 31 is installed in a conventional base 30for an incandescent bulb. The bulb 33 is sealed in the usual manner intoan extension 32- of the base. The relay 31, as may be seen in thefigure, has an oscillating leaf spring 34 laterally attached to the coilbody, an aperture in which movably accommodates the piston 35 with play.A snap spring 36 holds the leaf spring 34 in either extreme position. Atthe instroke of piston 35, the snap spring is forced into the otherposition near the end of the travel, whereas during the retarded returnstroke the same thing happens in the opposite direction owing to aprojection on the piston rod.

Pairs of contacts, not detailed, on the leaf Spring 34, close in the topsnap position. The pair of contacts of the light circuit may be actuatedin advance. The light circuit and coil circuit may be in series or inparallel, and the previously closed light circuit may be switched off orshort-circuited at the point of actuating contact.

This blinker light may of course be fitted with any base matching thatof a given incandescent lamp, and may be substituted for the latter whena blinking light is desired. This greatly simplifies the installation ofsignal systems of all kinds.

In the circuit diagram of FIG. 9, 40 is a battery forming a circuit withincandescent lamp &1, switch 42 and relay 43, which circuit isinterrupted by relay contact d4.

When switch 42 is turned on, both relay 43 and lamp 41 receive current,whereupon lamp 41 lights and is at once shut off by actuating of relay43. After a delay period, relay 43 goes on again, and the cycle repeatsitself. a

In parallel with the main switch 4-2, there is a line with resistance 45and test key 46. When test key 46 is actuated, the blinker light can beoperated via resistance 45 with switch 42 open, and the condition ofbattery charge can be observed by the result. The resistance 45 is sochosen that in case a predetermined minimum capacity of the battery hasbeen reached, the relay will fail to act and interrupt, so that thelight will burn steady. So long as the capacity of the battery isgreater than this, the light will blink.

The circuit of FIG. .10 differs in that the circuit of the battery andmain switch 42 branches via the movable intermediate contact 47 of therelay, alternatively via fixed contact 48 to light 41 or via movablecontact 49 to the relay coil 43. The mode of operation is essentiallythe same, since when the relay responds the movable contacts 47 and 49interrupt both the coil circuit of the relay and the light circuit.

The load resistance 45 is in the coil circuit as before, but normallyby-passed by the test key 46. For testing, depression of the test key 46puts the resistance 45 into the coil circuit, so that a blinking lightor a steady light will be obtained according to the condition ofdischarge of the battery. The principle is the same in both cases,namely that depending on the lowered service voltage of the battery asit discharges, the current required for the relay coil to respond willbe present above a certain residual charge capacity, while below thatpoint the relay will fail to respond and the light will burn steady.

What I claim is:

1. A solenoid relay comprising a core formed with an elongated chamberof substantially uniform transverse cross-section, a piston reciprocablein axial direction within said chamber and forming an armature, a coilsurrounding said core for electromagnetically displacing said pistonaxially upon energization of said coil, biasing means bearing on saidpiston and effective in a direction opposite to that of theelectromagnetic displacement of said piston to displace said piston insaid opposite direction upon de-energization of said coil,unidirectionally effective valve means in said core operable upondisplace ment of said piston in one of said directions for substantiallyfreely permitting the passage of a fluid out of said chamber, adjustablethrottle means on said core effective upon displacement of saidpiston-in the other of said directions for throttling the flow of saidfluid into said chamber, contact means secured to said core, acontactactuating member engageable with said contact means and slidablymounted on said piston for axial displacement relative thereto betweentwo limiting positions, and respective abutments on said pistonentraining said contact-actuating member in each of said limitingpositions for operating said contact means, said contact means and saidmember being provided with complementary means for releasably retainingsaid member intermediate said limiting positions.

2. A solenoid relay comprising a core formed with an elongated chamberof substantially uniform transverse cross-section, a piston reciprocablein axial direction within said chamber and forming an armature, a coilsurrounding said core for electromagnetically displacing said pistonaxially upon energizat-ion of said coil, biasing means bearing on saidpiston and effective in a direction opposite to that of theelectromagnetic displacement of said piston to displace said piston insaid opposite direction upon de-energization of said coil,unidirectionally effective valve means in said core operable upondisplacement of said piston in one of said directions for substantiallyfreely permitting the passage of a fluid out of said chamber, adjustablethrottle means on said core effective upon displacement of said pistonin the other of said directions for throttling the flow of said fluidinto said chamber, contact means in circuit with said coil secured tosaid core, a rod axially secured to said piston, an annularcontact-actuating member engageable with said contact means and slidablymounted on said rod for axial displacement relative thereto between twolimiting positions, and respective abutments on said rod entraining saidcontact-actuating member in each of said limiting positions foroperating said contact means, said contact means including a detent,said member being provided with an annular peripheral groove releasablyengageable by said detent for retaining said member.

3. A solenoid relay comprising a core formed with an elongated chamberof substantially uniform transverse cross-section, a piston reciprocablein axial direction within said chamber and forming an armature, a coilsurrounding said core for electromagnetically displacing said pistonaxially upon energizaiton of said coil, biasing means bearing on saidpiston and effective in a direction opposite to that of theelectromagnetic displacement of said piston to displace said piston insaid opposite direction upon de-energization of said coil,unidirectionally effective valve means in said core operable upondisplacement of said piston in one of said directions for substantiallyfreely permitting the passage of said fluid out of said chamber,adjustable throttle means on said core effective upon displacement ofsaid piston in the other of said directions for throttling the flow ofsaid fluid into said chamber, contact means in circuit with said coilsecured to said core, a rod axially secured to said piston, an annularcontact-actuating member engageable with said cont-act means andslidably mounted on said rod for axial displacement relative theretobetween two limiting positions, respective abutments on said rodentraining said contact-actuating member in each of said limitingpositions for operating said contact means, and spring means bearingupon said rod and said member urging the latter toward one of saidabutments, said contact mean including a detent, said member beingprovided with an annular peripheral groove releasably engageable by saiddetent for retaining said member.

4. A solenoid relay according to claim 2 wherein one of said abutmentscomprises a stop member axially adjustable on said rod.

5. A solenoid relay comprising a core formed with an elongated chamberof substantially uniform transverse cross-section, a piston reciprocablein axial direction within said chamber and forming an armature, a coilsurrounding said core for electromagnetically displacing said pistonaxially upon energization of said coil, biasing means in said chamberbearing on said piston and effective in a direction opposite to that ofthe electromagnetic displacement of said piston to displace said pistonin said opposite direction upon de-energization of said coil,unidirectionally effective valve means at one end of said chamberoperable upon displacement of said piston in one of said directions forsubstantially freely permitting the passage of a fluid out of saidchamber, adjustable throttle means at the same end of said chamber assaid valve means, said throttle means being effective upon displacementof said piston in the other of said directions for throttling the flowof said fluid into said chamber, contact means located adjacent saidcore, a contact-actuating member having a lost motion connection withsaid piston for axial displacement of the piston relative to the memberbetween two limiting positions, and respective abutments reciprocablymovable with said piston for entraining said contact-actuating member ineach of said limiting positions for operating said contact means, one ofsaid abutments being formed by a portion of the piston and the other ofsaid abutments being formed by a member adjustably mounted on thepiston.

(References on following page) 7 8 References Cited in the file of thispatent 2,323,459 De Valera July 6, 1943 TE PATENTS 2,333,604 WallaceNOV. 2, 1943 UNITED STA 5 2,432,730 Davey Dec. 16, 1947 725,259 Kltsee14, 1903 2,651,166 Dorfman Jan. 29, 1948 7281082 Sundh 1 2 5 2,716,171Mekelburg Aug. 23, 1955 2 g i'f 3 2,764,648 668661116 61; a1. Sept. 25,1956' a w 2,828,382 Davidson Mar. 25, 1958 1,493,259 Green May 6, 19241,584,063 Wilms May 11, 1926 1,585,988 Hesse May 25, 1926 m FOREIGNPATENTS 1,957,877 Young May 8, 1934 368,678 Germany 9, 1 3

2,284,481 Schwaneger May 26, 1942 569,211 Great Britain May 11, 1945

1. A SOLENOID RELAY COMPRISING A CORE FORMED WITH AN ELONGATED CHAMBEROF SUBSTANTIALLY UNIFORM TRANSVERSE CROSS-SECTION, A PISTON RECIPROCABLEIN AXIAL DIRECTION WITHIN SAID CHAMBER AND FORMING AN ARMATURE, A COILSURROUNDING SAID CORE FOR ELECTROMAGNETICALLY DISPLACING SAID PISTONAXIALLY UPON ENERGIZATION OF SAID COIL, BIASING MEANS BEARING ON SAIDPISTON AND EFFECTIVE IN A DIRECTION OPPOSITE TO THAT OF THEELECTROMAGNETIC DISPLACEMENT OF SAID PISTON TO DISPLACE SAID PISTON INSAID OPPOSITE DIRECTION UPON DE-ENERGIZATION OF SAID COIL,UNIDIRECTIONALLY EFFECTIVE VALVE MEANS IN SAID CORE OPERABLE UPONDISPLACEMENT OF SAID PISTON IN ONE OF SAID DIRECTIONS FOR SUBSTANTIALLYFREELY PERMITTING THE PASSAGE OF A FLUID OUT OF SAID CHAMBER, ADJUSTABLETHROTTLE MEANS ON SAID CORE EFFECTIVE UPON DISPLACEMENT OF SAID PISTONIN THE OTHER OF SAID DIRECTIONS FOR THROTTLING THE FLOW OF SAID FLUIDINTO SAID CHAMBER, CONTACT MEANS SECURED TO SAID CORE, ACONTACTACTUATING MEMBER ENGAGEABLE WITH SAID CONTACT MEANS AND SLIDABLYMOUNTED ON SAID PISTON FOR AXIAL DISPLACEMENT RELATIVE THERETO BETWEENTWO LIMITING POSITIONS, AND RESPECTIVE ABUTMENTS ON SAID PISTONENTRAINING SAID CONTACT-ACTUATING MEMBER IN EACH OF SAID LIMITINGPOSITIONS FOR OPERATING SAID CONTACT MEANS, SAID CONTACT MEANS AND SAIDMEMBER BEING PROVIDED WITH COMPLEMENTARY MEANS FOR RELEASABLY RETAININGSAID MEMBER INTERMEDIATE SAID LIMITING POSITIONS.